Beta, I post in your thread again under Bike Maintenance. Sheldon Brown sells an adapter shell for that bb. You'd probably need 26 inch rims, which are now the MTB standard, but hub width will be different. You can cut down an axle to fit. Though you really might be better off starting fresh. American children's bikes were their own heavy but unbreakable beasts, not meant to be interchangeable with high end adult bike parts.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72